Do Employees need to sign an NDA?

I work at an engineering firm. I recently was on a job site talking to a project planner. The are creating a propriety process for an Item that they have invented. The project planner said that he has an NDA with my firm. My assumption is that my boss (CEO) signed this. I was not made aware of this, I also have not signed an NDA with my company. Is my company protected in the case of a leak?